The apparatus to be described herein has general application as the plotter/printer component of a fixed data terminal or as an interface with a computer. It may be used in many business and industrial applications such as data acquisition or logging, inventory taking, stock picking, navigation, etc. For example, during an operation, an anesthesiologist is usually responsible for administering the drugs and for controlling various machines required to sustain the patient during the course of the operation. It is especially useful for recording medical and clinical data. The decisions which he makes are based to a great extent upon his observations of various patient functions which are monitored during the operation. These functions might include, for example, the patient's temperature, blood pressure, heart rate, blood gas concentration, etc. This information is acquired by various data-gathering devices connected to the patient and displayed by various recording machines.
Prior recorders of this type have not been entirely satisfactory, particularly for office, medical and clinical usage, for several reasons. They have tended to be rather large and heavy so that they cannot be moved about readily. Some recorders of the type which print data by impaction are quite noisy so that they are not suitable for use in an operating room or office environment. Some machines provide only an obstructed view of the data being recorded so that it is difficult for the operator to see the data and to make contemporaneous notes based thereon. Many of the present machines record data on paper tapes or scrolls and it is difficult for the user to write on those loose tapes. Ideally, the printer or plotter used by the physician or other operator should permit him to clearly see the information being recorded as it is being recorded and to make contemporaneous notes on the same record.
Finally, the prior plotters and printers only generate a single original record of the acquired data. For example, if copies of the record made during an operation are needed after the operation for placement in the hospital file, the surgeon's and anesthesiologist's files, or for other distribution, they are made at that time. It has been found, however, that after the operation, sometimes the only original record is changed, copies are made and then the original record is "lost" so that the only available records are incorrect or inconsistent copies. It would be highly desirable, then, especially for medical and clinical applications, that the recorder produce two or more original records of the data being recorded.